1. Field of the Invention
The invention relates to semiconductor circuits, and in particular to semiconductor circuits capable of selecting a corresponding adjusting parameter to adjust the received signal according to different voltages and frequencies.
2. Description of the Related Art
Semiconductor memory devices, such as dynamic random access memories (DRAMs), usually have an internal voltage regulator to convert an external power voltage into an interval power voltage because the external power voltage is more unstable. For example, the internal power voltage is provided to power a memory array (or cell array) in the memory device and peripheral control circuits.
Delay and margin between internal signals in the semiconductor devices cannot be assured if core logic circuits (i.e. memory array and the peripheral control circuits) are powered by the external power voltage directly. Thus, when the memory device is powered by the external power voltage directly, to assure delay and margin between internal signals in the semiconductor devices have became very important.